METHOD CAPABLE OF REALIZING PREPARATION AND IN-SITU SEPARATION OF OLIGOMERIC RICINOLEATE

Abstract

The disclosure is about a method capable of realizing the preparation and in-situ separation of the oligomeric ricinoleate, which uses the ricinoleic acid as raw material, and uses a protonic acid-type ionic liquid as a catalyst to cause the dehydration and esterification reactions between ricinoleic acid molecules. By continuously distilling out the generated water under a reduced pressure, the oligomeric ricinoleate with a polymerization degree of 2 to 10 is obtained. After the reaction, a method of washing with water or static stratification is selected to recover the catalyst according to the miscibility of the catalyst and reaction system. In his disclosure, renewable raw materials are used, the process is clean and pollution-free, and the operation is simple.

Claims

1. A method capable of realizing preparation and in-situ separation of the oligomeric ricinoleate, which uses the ricinoleic acid as raw material, and uses a Bronsted acidic ionic liquid as catalyst to cause dehydration and esterification reactions between ricinoleic acid molecules, and takes out generated water by using a vacuum pump, thus being capable of obtaining an oligomeric ricinoleate with a polymerization degree lower than 10, comprising the following steps of: step 1: putting the ricinoleic acid and the catalyst into a reaction flask; step 2: starting the vacuum pump to adjust the vacuum degree of the reaction system, heating to a reaction temperature under a stirring condition, and starting the dehydration and esterification reactions; step 3: after the reaction, removing the catalyst, and finally obtaining a product, which is the oligomeric ricinoleate.

2. The method capable of realizing the preparation and in-situ separation of the oligomeric ricinoleate according to claim 1, wherein after the reaction, the catalyst is removed by a method of washing with water or static stratification according to miscibility of the ionic liquid catalyst with the reaction system; for the ionic liquid that is soluble in the reaction system at room temperature, water washing was used to separate the catalyst with the product while for the ionic liquid which is immiscible with the reaction system at room temperature, static stratification and dumpling was applied.

3. The method capable of realizing the preparation and the in-situ separation of the oligomeric ricinoleate according to claim 1, wherein the used raw material ricinoleic acid has an acid value of 150 mg KOH/g to 190 mg KOH/g.

4. The method capable of realizing the preparation and the in-situ separation of the oligomeric ricinoleate according to claim 1, wherein the cation of the ionic liquid catalyst is one or more of N-methylpyrrolidone ion ([NMP].sup.+), N-butylsulfonate pyridinium ion ([HSO.sub.3-BPy].sup.+), N-(4-butanesulfonic acid)triethylamine ion ([HSO.sub.3-BNEt.sub.3].sup.+), 1-butanesulfonic acid-3-methylimidazole ion ([HSO.sub.3-BMim].sup.+), or 1-butanesulfonic acid-1,8-diazabicyclo[5.4.0]undec-7-ene ion ([HSO.sub.3-BDBU]).sup.+); and the anion of the ionic liquid catalyst is one or more of hydrogen sulfate (HSO.sub.4.sup.−), dihydrogen phosphate (H.sub.2PO.sub.4.sup.−), trifluoromethanesulfonic acid ion (CF.sub.3SO.sub.3.sup.−), or p-toluenesulfonic acid ion PTSA.sup.−).

5. The method capable of realizing the preparation and the in-situ separation of the oligomeric ricinoleate according to claim I wherein a dosage of the catalyst ranges from 1 wt. % to 30 wt. %.

6. The method capable of realizing the preparation and the in-sitz separation of the oligomeric ricinoleate according to claim 1, wherein the dehydration and esterification reactions are performed at the temperature of 160° C. to 230° C. and a vacuum degree of 70 kPa to 0 kPa, and last for 2 hours to 16 hours.

7. The method capable of realizing the preparation and the in-situ separation of the oligomeric ricinoleate according to claim 1, wherein the obtained oligomeric ricinoleate has an acid value of 10 mg KOH/g to 90 mg KOH/g, which corresponds to a polymerization degree less than or equal to 10; at 40° C., the kinematic viscosity of the product is less than or equal to 1,000 mm.sup.2/s; and at 100° C. the kinematic viscosity is less than or equal to 100 mm.sup.2/s.

8. An oligomeric ricinoleate prepared by the method of claim 1, wherein the final product oligomeric ricinoleate has a structural formula as follows: ##STR00003## wherein, n is an integer from 2 to 10.

9. The oligomeric ricinoleate according to claim 8, wherein after the reaction, the catalyst is removed by a method of washing with water or static stratification according to miscibility of the ionic liquid catalyst with the reaction system; for the ionic liquid that is soluble in the reaction system at room temperature, water washing was used to separate the catalyst with the product while for the ionic liquid which is immiscible with the reaction system at room temperature, static stratification and dumpling was applied.

10. The oligomeric ricinoleate according to claim 8, wherein the used raw material ricinoleic acid has an acid value of 150 mg KOH/g to 190 mg KOH/g.

11. The oligomeric ricinoleate according to claim 8, wherein the cation of the ionic liquid catalyst is one or more of N-methylpyrrolidone ion ([NMP ].sup.+), N-butylsulfonate pyridinium ion ([HSS.sub.3-BPyr].sup.+), N-(4-butanesulfonic acid)triethylamine ion ([HSO.sub.3-BNEt.sub.3].sup.+), 1-butanesulfonic acid-3-methylimidazole ion ([HSO.sub.3-BMim].sup.+), or 1-butanesulfonic acid-1,8-diazabicyclo[5.4.0]undec-7-ene ion ([HSO.sub.3-BDBU]).sup.+); and the anion of the ionic liquid catalyst is one or more of hydrogen sulfate (HSO.sub.4.sup.−), dihydrogen phosphate (H.sub.2PO.sub.4.sup.−), trifluoromethanesulfonic acid ion (CF.sub.3SO.sub.3.sup.−), or p-toluenesulfonic acid ion PTSA.sup.−).

12. The oligomeric ricinoleate according to claim 8, wherein a dosage of the catalyst ranges from 1 wt. % to 30 wt. %.

13. The oligomeric ricinoleate according to claim 8, wherein the dehydration and esterification reactions are performed at the temperature of 160° C. to 230° C. and a vacuum degree of 70 kPa to 0 kPa, and last for 2 hours to 16 hours.

14. The oligomeric ricinoleate according to claim 8, wherein the obtained oligomeric ricinoleate has an acid value of 10 mg KOH/g to 90 mg KOH/g, which corresponds to a polymerization degree less than or equal to 10; at 40° C., the kinematic viscosity of the product is less than or equal to 1,000 mm.sup.2/s; and at 100° C., the kinematic viscosity is less than or equal to 100 mm.sup.2/s.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG. 1 is the reaction formula for synthesis of oligomeric ricinoleate.

[0032] FIG. 2 is the FT-IR spectrum of a product.

[0033] FIG. 3 is the .sup.1H NMR spectrum of the product.

[0034] FIG. 4 is the .sup.13C NMR spectrum of the product.

[0035] FIG. 5 is the ESI-MS spectrum of the product.

DETAILED DESCRIPTION

[0036] The disclosure is about a method capable of realizing preparation and in-situ separation of the oligomeric ricinoleate. In order to meet needs of industrialization, an environmentally friendly and easily operated preparation method with high-yield of oligomeric ricinoleate is developed with the renewable ricinoleic acid as starting material through experimental screening. The positive effect of the disclosure contains the use of bio-base and renewable starting material, recyclable catalyst, simple operation, green process and adjustable product with excellent properties.

Embodiment 1

[0037] 10 g of ricinoleic acid and 0.5 g of N-methylpyrrolidone hydrosulfate ([NMP]HSO.sub.4) were added into a reaction flask, a vacuum pump was started to adjust a vacuum degree of the reaction system to be 50 kPa, and meanwhile, the mixture was stirred and heated to 160° C. With the progress of the reaction, water was continuously pumped out, and the reaction was stopped 5 hours later. Then, the catalyst was removed by washing with water to obtain the product, with a yield of 93%. It was measured that the acid value of the product was 76 mg KOH/g, which corresponds to an average polymerization degree about 2. The kinematic viscosity of the resulting product was 163.8 mm.sup.2 at 40° C., and the kinematic viscosity was 31.4 mm.sup.2/s at 100° C.

[0038] Preparation method of the catalyst [NMP]HSO.sub.4: equivalent sulfuric acid was added into 0.1 mol (9.9 g) of N-methylpyrrolidone. The reaction mixture was stirred at 80° C. for 24 hours, and then dried in vacuum at 80° C. for 24 hours to obtain the [NMP]HSO.sub.4.

Embodiment 2

[0039] 10 g of ricinoleic acid and 1 g of N-butylsulfonate pyridinium p-toluenesulfonate ([HSO.sub.3-BPy]PTSA) were added into a reaction flask, a vacuum pump was started to adjust the vacuum degree of the reaction system to be 30 kPa, and meanwhile, the mixture was stirred and heated to 230° C. With the progress of the reaction, water was continuously pumped out, and the reaction was stopped 2 hours later. Then, the catalyst was removed by washing with water to obtain a product. The final yield of the product was 93% with an acid value of 27 mg KOH/g, which corresponded to an average polymerization degree about 8. The kinematic viscosity of the resulting product was 884.4 mm.sup.2/s at 40° C., and the kinematic viscosity was 89.7 mm.sup.2/s at 100° C.

[0040] Preparation method of the catalyst [HSO.sub.3-BPy]PTSA: 0.05 mol (10.8 g) of N-butylsulfonate pyridinium inner salt was added into 50 mL of dichloromethane, and then equivalent p-toluenesulfonic acid was added. The reaction mixture was stirred at 60° C. for 4 hours, and then a viscous liquid on an upper layer was separated, which was then washed twice with ether, and dried in vacuum at 100° C. for 24 hours to obtain the [HSO.sub.3-BPy]PTSA.

Embodiment 3

[0041] 10 g of ricinoleic acid and 1.5 g of N-(4-butanesulfonic acid) triethylamine dihydrogenphosphat ([HSO.sub.3-BNEt.sub.3]H.sub.2PO.sub.4) were added into a reaction flask, a vacuum pump was started to adjust the vacuum degree of the reaction system to be 70 kPa, and meanwhile, the mixture was stirred and heated to 200° C. With the progress of the reaction, water was continuously pumped out, and the reaction was stopped 6 hours later. Then, the catalyst was removed by washing with water to obtain the product. The final product yield was 92% with an acid value of 35 mg KOH/g, which corresponded to an average polymerization degree about 6. The kinematic viscosity of the resulting product was 712.5 mm.sup.2/s at 40° C., and the kinematic viscosity was 81.7 mm.sup.2/s at 100° C.

[0042] Preparation method of the catalyst [HSO.sub.3-BNEt.sub.3]H.sub.2PO.sub.4: 0.05 mol (11.9 g) of N-(4-butanesulfonic acid) triethylamine inner salt was added into 50 mL of dichloromethane, and then equivalent phosphoric acid was added. The reaction mixture was stirred at 60° C. for 4 hours, and then a viscous liquid on an upper layer was separated, which was then washed twice with ether, and dried in vacuum at 100° C. for 24 hours to obtain the [HSO.sub.3-BNEt.sub.3]H.sub.2PO.sub.4.

Embodiment 4

[0043] 10 g of ricinoleic acid and 2 g of 1-butanesulfonic acid-3-methylimidazolium trifluoromethanesulfonate ([HSO.sub.3-BMim]CF.sub.3SO.sub.3) were added into a reaction flask, a vacuum pump was started to adjust the vacuum degree of the reaction system to be 30 kPa, and meanwhile, the mixture was stirred and heated to 210° C. With the progress of the reaction, water was continuously pumped out, and the reaction was stopped 4 hours later. Then, the catalyst was removed by washing with water to obtain the product. The final product yield was 94% with an acid value of 56 mg KOH/g, which corresponded to an average polymerization degree was about 3 to 4. The kinematic viscosity of the resulting product was 391.6 mm.sup.2/s at 40° C., and the kinematic viscosity was 42.2 mm.sup.2/s at 100° C.

[0044] Preparation method of the catalyst [HSO.sub.3-BMim]CF.sub.3SO.sub.3: 0.05 mol (10.9 g) of 1-butanesulfonic acid-3-methylimidazolium inner salt was added into 50 mL of dichloromethane, and then equivalent trifluoromethanesulfonic acid was added. The reaction mixture was stirred at 60° C. for 4 hours, and then a viscous liquid on an upper layer was separated, which was then washed twice with ether, and dried in vacuum at 100° C. for 24 hours to obtain the [HSO.sub.3-BMim]CF.sub.3SO.sub.3.

[0045] Embodiment 5

[0046] 1 g of ricinoleic acid and 0.01 g of N-butylsulfonate pyridinium dihydrogenphosphat ([HSO.sub.3-BPy]H.sub.2PO.sub.4) were added into a reaction flask, and reacted under a normal pressure, and meanwhile, the mixture was stirred and heated to 190° C. With the progress of the reaction, water was continuously pumped out, and the reaction was stopped 16 hours later. Then, the catalyst was removed by washing with water to obtain a product. The final product yield was 91% with an acid value of 20 mg KOH/g, which corresponded to an average polymerization degree about 9. The kinematic viscosity of the product was 911.4 mm.sup.2/s at 40° C., and the kinematic viscosity was 91.7 mm.sup.2/s at 100° C.

[0047] Preparation method of the catalyst [HSO.sub.3-BPy]H.sub.2PO.sub.4: 0.05 mol (10.8 g) of N-butylsulfonate pyridinium inner salt was added into 50 mL of dichloromethane, and then equivalent phosphoric acid was added. The reaction mixture was stirred at 60° C. for 4 hours, and then a viscous liquid on an upper layer was separated, which was then washed twice with ether, and dried in vacuum at 100° C. for 24 hours to obtain the [HSO.sub.3-BPy]H.sub.2PO.sub.4.

Embodiment 6

[0048] 0.5 g of ricinoleic acid and 0.025 g of N-(4-butanesulfonic acid) triethylamine disulfate ([HSO.sub.3-BNEt.sub.3]HSO.sub.4) were added into a reaction flask, a vacuum pump was started to adjust a vacuum degree of a reaction system to be 70 kPa, and meanwhile, the mixture was stirred and heated to 210° C. With the progress of the reaction, water was continuously pumped out, and the reaction was stopped 3 hours later. Then, the catalyst was removed by washing with water to obtain a product. The final product yield was 93% with an acid value of 39 mg KOH/g, which corresponded to an average polymerization degree about 6. The kinematic viscosity of the product was 698.5 mm.sup.2/s at 40° C., and the kinematic viscosity was 79.5 mm.sup.2/s at 100° C.

[0049] Preparation method of the catalyst [HSO.sub.3-BNEt.sub.3]HSO.sub.4: 0.05 mol (11.9 g) of N-(4-butanesulfonic acid) triethylamine inner salt was added into 50 mL of dichloromethane, and then equivalent sulfuric acid was added. The reaction mixture was stirred at 60° C. for 4 hours, and then a viscous liquid on an upper layer was separated, which was then washed twice with ether, and dried in vacuum at 100° C. for 24 hours to obtain the [HSO.sub.3-BNEt.sub.3] HSO.sub.4.

Embodiment 7

[0050] 50 g of ricinoleic acid and 5 g of catalyst 1-butanesulfonic acid-1, 8-diazabicyclo [5 .4.0]undec-7- ene dihydrogenphosphat ([HSO.sub.3-BDBU]H.sub.2PO.sub.4) were added into a reaction flask, a vacuum pump was started to control the vacuum degree of the reaction system to 50 kPa, and meanwhile, the mixture was stirred and heated to 170° C. With the progress of the reaction, water was continuously pumped out, and the reaction was stopped 16 hours later. When the reaction system was cooled to room temperature and standed for 1 hour, it could be found that the product and the catalyst were stratified with the product locating on the upper layer and the catalyst locating on the lower layer. Thus the product and the catalyst could be separated by simple dumping. The final yield of the product was 95% with an acid value of 17 mg KOH/g, which corresponded to an average polymerization degree about 10. The kinematic viscosity of the resulting product was 962.5 mm.sup.2/s at 40° C., and the kinematic viscosity was 95.0 mm.sup.2/s at 100° C.

[0051] Preparation method of the catalyst [HSO.sub.3-BDBU]H.sub.2PO.sub.4: 0.05 mol (14.4 g) of 1-butanesulfonic acid-1,8-diazabicyclo[5.4.0]undec-7-ene inner salt was added into 50 mL of dichloromethane, and then equivalent phosphoric acid was added. The reaction mixture was stirred at 60° C. for 4 hours, and then a viscous liquid on an upper layer was separated, which was then washed twice with ether, and dried in vacuum at 100° C. for 24 hours to obtain the [HSO.sub.3-BDBU]H.sub.2PO.sub.4.

Embodiment 8 Investigation on Dosage of Catalyst

[0052] 10 g of ricinoleic acid was added into a reaction flask, the usage of the catalyst 1 -butane sulfonic acid-1, 8-diazabicyclo[5.4.0]undec-7-ene dihydrogenphosphat ([HSO.sub.3-BDBL]H.sub.2PO.sub.4) were set at respectively 1%, 5%, 15%, 20%, and 30% of a mass ratio to the raw material and a vacuum pump was started to regulate the vacuum degree of the reaction system to 50 kPa. Meanwhile, the mixture was stirred and heated to 200° C. With the progress of the reaction, water was continuously pumped out, and the reaction was stopped 5 hours later. When the reaction system was cooled to room temperature and standed for 1 hour, the product and the catalyst were separated by static stratification and simple dumping. The effect of the dosage of the catalyst on a yield and a property of the product could be obtained, as shown in Table 1.

TABLE-US-00001 TABLE 1 Physicochemical properties of products prepared with different dosages of catalyst Dosage Average Kinematic viscosity of catalyst Acid value polymerization mm.sup.2/s wt. % mg KOH/g degree Yield % 40° C. 100° C.  1 120 1-2 91 120.3 21.4  5 103 1-2 91 147.8 27.7 15  52 4 93 406.6 45.3 20  50 4 92 420.5 48.3 30  40 5 94 710.5 80.2

Embodiment 9 Investigation on Vacuum Degree of Reaction

[0053] 10 g of ricinoleic acid and 1.5 g of catalyst 1-butanesulfonic acid-1, 8-diazabicyclo [5.4.0]undec-7- ene dihydrogenphosphat ([HSO.sub.3-BDBU]H.sub.2PO.sub.4) were added into a reaction flask, a vacuum pump was started to adjust the vacuum degree of the reaction system between 0 kPa and 70 kPa respectively, and meanwhile, the mixture was stirred and heated to 190° C. With the progress of the reaction, water was continuously pumped out, and the reaction was stopped 8 hours later. When a reaction system was cooled to room temperature and standed for 1 hour, the product and catalyst were separated by static stratification and simple dumping. The effect of a vacuum degree on the yield and property of the product could be obtained, as shown in Table 2.

TABLE-US-00002 TABLE 2 Physicochemical properties of products prepared at different vaccum degrees Average Kinematic viscosity Vacuum Acid value polymerization mm.sup.2/s degree kPa mg KOH/g degree Yield % 40° C. 100° C. 70  43 5 95 510.3 54.3 50  44 4-5 95 507.5 53.1 30  52 4 92 406.2 45.7 20  63 3 93 368.9 41.5  0 101 1-2 90 223.1 34.5

Embodiment 10 Investigation on Recycling and Reuse of Catalyst

[0054] 10 g of ricinoleic acid and 3 g of 1-butanesulfonic acid-1, 8-diazabicyclo [5.4.0 ]undec-7-ene dihydrogenphosphat ([HSO.sub.3-BDBU]H.sub.2PO.sub.4) were added into a reaction flask, a vacuum pump was started to adjust the vacuum degree of the reaction system to be 50 kPa, and meanwhile, the mixture was stirred and heated to 220° C. With the progress of the reaction, water was continuously pumped out, and the reaction was stopped 5 hours later. Then, static stratification was carried out and the product A located on the upper layer was dumped and weighed to calculate the yield. The catalyst left in the reaction flask was weighed to be 2.8 g. 10 g of fresh ricinoleic acid was then added into the reaction flask containing the recycled catalyst to start another preparation process for oligomeric ricinoleate. With the same procedure, the above esterification operation was lasted for 5 hours, and then the product and the catalyst were separated by static stratification and dumping again to obtain the product B. Meanwhile, the remaining catalyst was weighed as 2.7 g, and 10 g of fresh ricinoleic acid was continuously added into the reaction flask containing the recycled catalyst. With the same operating conditions, the reaction was lasted for 5 hours to obtain the product C. Results of physicochemical properties of the products A, B and C measured refer to Table 3.

TABLE-US-00003 TABLE 3 Physicochemical properties of products prepared by recycling catalyst Average Kinematic viscosity Acid value polymerization mm.sup.2/s Product mg KOH/g degree Yield % 40° C. 100° C. A 44 5 93 568.6 64.8 B 47 4-5 94 519.4 59.4 C 52 4 94 493.5 57.2

[0055] The embodiment indicates that the ionic liquid has a good stability and can be reused in synthesis of an oligomeric ricinoleate.

Embodiment 11 Effect of Combination of Catalysts on Reaction

[0056] 10 g of ricinoleic acid and 2 g of mixture of 1-butanesulfonic acid-3-methylimidazolium trifluoromethanesulfonate ([HSO.sub.3-BMim]CF.sub.3SO.sub.3) and N-butylsulfonate pyridinium dihydrogenphosphat ([HSO.sub.3-BPy]H.sub.2PO.sub.4) with a mass ratio of 1:1 were added into a reaction flask, a vacuum pump was started to adjust the vacuum degree to be 50 kPa, and meanwhile, the mixture was stirred and heated to 230° C. With the progress of the reaction, water was continuously pumped out, and the reaction was stopped 8 hours later. The catalyst was removed by washing with water. The final yield of the product was 92% with an acid value of the product to be 20 mg KOH/g, which corresponded to an average polymerization degree about 9. The kinematic viscosity of the product was 920.1 mm.sup.2/s at 40° C., and the kinematic viscosity was 92.3 mm.sup.2/s at 100° C.

[0057] Characterization of product oligomeric ricinoleate:

[0058] Appearance: yellow oily liquid

[0059] FT-IR (KBr) Vmax/cm.sup.−1: 3416.44, 3010.55, 2927.89, 2855.81, 1733.38, 1711.66, 1464.22, 1245.41, 1183.74, 725.11; ESI-MS: m/z (+) 579.3, 876.6, 1139.7, 1437.8, 1716.9, 1997.1 (as shown in FIG. 1).

[0060] .sup.1H NMR (400 MHz, CDCl.sub.3) δ: 0.85-0.88 (t, J=3.9 Hz, 3H), 1.26-1.29 (m, 16H), 1.51-1.60 (m, 4H), 2.00-2.01 (m, 2H), 2.25-2.26 (m, 4H), 4.86-4.89 (m, 1H), 5.30-5.46 (m, 2H) ppm (as shown in FIG. 2).

[0061] .sup.13C NMR (100 MHz, CDCl.sub.3) δ: 14.08, 22.58, 25.11, 25.35, 27.20-27.35, 29.03-29.71, 31.75, 31.98, 33.62, 34.65, 73.69, 124.30, 132.51, 173.58 ppm (as shown in FIG. 3).

[0062] ESI-MS: m/z (+) 579.3, 876.6, 1139.7, 1437.8, 1716.9, 1997.1 (as shown in FIG. 4).

[0063] The foregoing describes several embodiments of the disclosure in detail, which cannot be regarded as limiting the implementation scope of the disclosure. All equal changes and improvements made according to the application scope of the disclosure shall still fall within the coverage scope of the patent of the disclosure.